Dr Kidman's wife, Janelle, is in Sydney and it is understood Nicole was in Nashville at the time of his death.

Dr Kidman, a psychologist and Director of the Health Psychology Unit at Sydney's Royal North Shore Hospital, was awarded an Order of Australia medal in 2005 for his contributions to clinical psychology.

He was a regular speaker on radio and television; and a contributor to The Australian Women's Weekly; highly valued for his ability to give expression to the frustrations of modern life.

In one of his last public statements, he wrote of the pointless pursuit of happiness.

In the article titled "Forget happiness, search for meaning", Dr Kidman wrote about the importance of striving for achievable goals in life, with a focus on being contented with what you have rather than on a life of material wealth.

"Humans are very good at denigrating themselves and their self-worth," he wrote. "For example, I should be successful and I must be attractive. There is nothing wrong with preferring and working hard to achieve these objectives but when you demand that they happen, then you are in for a difficult time. A crucial strategy used in therapy is to get people to accept themselves and others unconditionally.

"People who achieve contentment are liked. They are good role models, are normally empathetic and are sought after as friends. These attributes give meaning to their lives; they help other people and achieve contentment with the cards they have been dealt.”

The news of the passing of Dr Kidman has been met with shock and sadness at The Weekly, where Editor-in-Chief, Helen McCabe today addressed staff and paid tribute to "a man of principle and honour".